Integrated circuits are made possible by processes which produce intricately patterned material layers on substrate surfaces. Producing patterned material on a substrate requires controlled methods for removal of exposed material. Chemical etching is used for a variety of purposes including transferring a pattern in photoresist into underlying layers, thinning layers, or thinning lateral dimensions of features already present on the surface. Often it is sought to have an etch process that etches one material faster than another facilitating, for example, a pattern transfer process. Such an etch process is said to be selective to the first material. As a result of the diversity of materials, circuits, and processes, etch processes have been developed with a selectivity towards a variety of materials.
Dry etches produced in local plasmas formed within the substrate processing region can penetrate more constrained trenches and exhibit less deformation of delicate remaining structures. However, local plasmas can damage the substrate through the production of electric arcs as they discharge. Plasmas additionally may sputter or otherwise degrade chamber components often requiring replacement of internal parts. Protecting chamber components can be performed by seasoning the chamber, which may increase process queue times and may be a disadvantage to adequate throughput.
Thus, there is a need for improved system components that can be used in plasma environments effectively while providing suitable degradation profiles. These and other needs are addressed by the present technology.